Substrates based on sugarcane bagasse in the production of Eucalyptus camaldulensis Dehnh seedlings

‘Seedling’ quality is strongly influenced by substrate composition, while commercial substrates may increase production costs. Sugarcane bagasse, an agroindustrial residue widely available in Pernambuco, Brazil, is a promising alternative for substrate formulation. This study evaluated sugarcane bagasse as a organic compost (COB) and biochar produced at 300 °C (BIO300) and 500 °C (BIO500) for the production os Eucalyptus camaldulensis sendlings.Nine substrate treatments, including a commercial substrate (SC) and vermiculite (VER) as references, were assessed. Substrates were characterized through bulk density, Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). Seedling growth, quality indices and Pearson correlations were avaluated 120 days after sowing. Significant differences were observed among treatments. SEM and EDS analyses showed structural and elemental changes with increasing carbonization temperature. The substrate composed of 100% surgarcane bagassse organic compost produced the highest seedling height, collar diamenter, dry mass and Dickson Quality Index, outperforming all other treatments. These results domonstrate that sugarcane bagasse organic compost is a sustainable, low-cost and regionally avaible alternative to commercial substrates for forest seedlind productio. .